This application is based upon and claims the benefit of priority from Japanese Patent Applications No. 2000-156804 filed on May 26, 2000 and No. 2001-18993 filed on Jan. 26, 2001 in Japan, the entire contents of which are incorporated by reference.
(1) Field of the Invention
The present invention relates to a hood for an endoscope used for endoscopy and endoscopic operations. More particularly, the present invention relates to an endoscope hood which is approximately cylindrical and installed on the distal end of the endoscope insertion part. In the hood, a mucous membrane is absorbed and swells. A high frequency snare cuts the basal portion of the swelling mucous membrane.
(2) Description of the Prior Art
In the prior art, an operation by means of an endoscope is done without cutting an abdominal wall open. A high frequency snare is introduced into the body through a channel of an endoscope is used for early cancer of gullet and stomach, in order to cut a mucous membrane of a diseased part.
Generally in such an endoscopic mucosal resection, a subcylindrical hood is installed on the distal end of the insertion part of an endoscope. A mucous membrane is drawn into the hood and swells. The basal part is caught and cut with a high frequency snare. It is important to precisely locate a wire of a high frequency snare on the basal part of an upheaval-shaped mucous membrane drawn in an endoscope hood.
Japanese Utility Model Laid-Open Publication No. 6-75402 discloses a hood for an endoscope comprising a transparent hard cap part and a connection part connecting the cap part to the end portion of an endoscope and nails which protrude from the end portion of the cap part. In Japanese Patent Laid-Open Publication No. 9-187415, an endoscope has a channel located outside the transparent cylindrical cap part.
(2) Description of the Related Art
In Japanese Utility Model Laid-Open No. 6-75402 bulletin, a high frequency snare passes through an endoscope channel. In this case, an end aperture part of the endoscope channel is spaced inwardly from the internal surface of a hood. Accordingly, it is difficult to widen the loop of the high frequency snare introduced into the hood through the endoscope channel.
Furthermore, a high frequency snare through an endoscope channel and other endoscopic treating instruments cannot be used simultaneously. In particular, it cannot be confirmed whether or not a high frequency snare catches muscular coats, since the high frequency snare and an ultrasonic probe cannot pass through simultaneously. In addition, suction power becomes weak since suction is done with an endoscope channel blocked by a high frequency snare. Therefore, a mucous membrane does not swell enough. In Japanese Patent Laid-Open No. 9-187415 bulletin, before an endoscope is inserted into the body, a high frequency snare is inserted into a channel disposed on the outside of a cap part. The loop of the high frequency snare is widened and held outside the cap part. In this case the loop of the snare wire is widened and positioned around the cap part outside the body. Therefore, the endoscope has to be pulled out of the body in order to hang the snare again. This makes the operation more difficult. In addition, the loop of the snare wire, when widened and hung outside the cap part is hard to come off the cap part.
Therefore, it is an object of the present invention to provide a hood for an endoscope with which endoscopic mucosal resection is safely and easily operated using a high frequency snare.
Accordingly, the present invention provides a hood for an endoscope having a preferably transparent and substantially cylindrical cap part which defines a cavity and is mounted on the end portion of an endoscope insertion part; an endoscope mounting part for detachably fixing the cap part to the end portion of the insertion part of the endoscope; and a flexible tube whose end portion is connected to an opening communicating with the cavity of the cap part so that an endoscopic treating instrument is removably inserted. Due to the above-mentioned structure, endoscopic treating instruments such as an ultrasonic probe are brought into the body through a channel of the endoscope and a high frequency snare is brought through the flexible tube. Thus, by using the ultrasonic probe or the like, it can be confirmed how the high frequency snare binds a mucous membrane and muscular coats so that the mucous membrane is resected more safely. In addition, an operation becomes easier, since an operator can use the high frequency snare through the flexible tube and such endoscopic treating instruments through endoscope channels as an injection needle and a high frequency knife which are necessary to resect a mucous membrane.
Furthermore, the looping of a snare wire becomes easier, since the looping can be repeated in the cap part without pulling out the endoscope. Also, since a channel of the endoscope can be empty, a mucous membrane is surely sucked and swells.